Hi,

I wonder if anyone can help with a z probe issue I have.

I have a Chinese CNC3040 cnc machine, with a arduino to db25 adapter - basically converting grbl to mach3.

I have the A5 and GND pins wired for a z probe in GRBL.

I am using BCNC software and when i short the 2 z probe wires - I get confirmation that the zero point has been reached.

When I carry out a z probe routine on the actual cnc (gnd to chassis and z probe to milling bit) - the probe stops short of the zero point and I have to run the routine 2 or 3 times before it actually get to the correct zero point.

I have checked all the wiring on my 3040 - as they are known for bad GND`s. I have also checked the continuity from the chassis to the milling bit to make sure its open circuit.

Does anyone have any ideas how to solve this problem?

Do I need a resistor or capacitor to smooth the z probe line?

Many thanks in advance.

Iain